Systems and methods for placing and analyzing test plots

ABSTRACT

Systems and methods and apparatus for placing a plot in an agricultural field. Systems and methods are also provided for selecting a plot location based on primary and secondary parameters, for selecting a plot location based on user-defined parameters, and for allowing a user to accept or reject proposed plot placement.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/125,698, filed May 23, 2014, which is a national stage application ofInternational Application No. PCT/US2012/042281, filed Jun. 13, 2012,which claims the benefit of U.S. Provisional Application No. 61/496,486,filed Jun. 13, 2011, each of which is incorporated by reference hereinin its entirety.

BACKGROUND

In recent years, farmers and agronomists have increasingly recognizedthe importance of population (i.e., the number of seeds planted peracre) in maximizing yield and profit in the cultivation of corn andother crops. There is similar interest in maximizing the economicbenefit of other crop inputs such as nitrogen. Thus there is a need inthe art for systems and methods for varying application rates and fordetermining relationships between application rates and yield.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of an embodiment of a row crop planter.

FIG. 2 is a top view of an embodiment of a row crop combine.

FIG. 3 schematically illustrates an embodiment of a system forgathering, comparing and analyzing planting and yield data.

FIG. 4 is a top view of the planter of FIG. 1 planting a field includinga test plot.

FIG. 5 is a top view of the combine of FIG. 2 harvesting the field andtest plot of FIG. 4.

FIG. 6 is a top view of the planter of FIG. 1 planting a field includingmultiple test plots.

FIG. 7 is a top view of the planter of FIG. 1 planting a field includingside-by-side test plots planted in a single pass.

FIG. 8 is a top view of the planter of FIG. 1 planting a field includingend-to-end test plots planted in a single pass.

FIG. 9 is a top view of the planter of FIG. 1 planting a field includinga single test plot planted in multiple passes.

FIG. 10 illustrates the dimensions and location of a test plot overlaidon a soil type map of a field.

FIG. 11 illustrates the dimensions and location of multiple test plotsoverlaid on a soil type map of a field.

FIG. 12 illustrates the overlay of two layers of spatially referencedagricultural data.

FIG. 13 illustrates an embodiment of a process for placing test plotsand analyzing yield data.

FIG. 14 illustrates an embodiment of a process for selecting test plotlocations.

FIG. 15 illustrates an embodiment of a process for analyzing test plotyield results.

FIG. 16 illustrates an embodiment of a user interface screen forentering user input.

FIG. 17 illustrates an embodiment of a display screen for displaying thelocation of a test plot during harvesting operations.

FIG. 18 illustrates an embodiment of a display screen for displayingplot placements within a field boundary.

DESCRIPTION Field Data Gathering System

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIG. 1illustrates a top view of a tractor 5 pulling a planter 10 used to plantrow crops. The planter 10 includes a frame 12, in which a toolbar 14extends transversely as a mounting structure for row units 16, each ofwhich is configured to plant seeds in a row as is known in the art. Eachrow unit 16 is preferably configured to plant at variable populationrates (i.e., number of seeds per acre) as is disclosed in U.S. Pat. No.6,863,006, the disclosure of which is hereby incorporated herein in itsentirety by reference. The planter 10 preferably includes one or moredrives 427 (FIG. 3), such as hydraulic or electric drives as are knownin the art, for varying the population rate planted by each row unit 16or a group of row units. The planter 10 further preferably includes oneor more clutches 425 (FIG. 3) for engaging and disengaging the drives tostop or resume planting at each row units 16 or group of row units. Theplanter 10 further preferably includes one or more seed sensors 420(FIG. 3) for detecting the time of seed deposition as well as thepopulation rate planted by each row unit 16. In some embodiments, theseed sensors 420 comprise optical-type sensors such as those disclosedin U.S. Pat. No. 5,936,234. The population rate is preferably controlledby a cab-mounted planter monitor 50, which preferably incorporates agraphical user interface 55, such as disclosed in Applicant's co-pendingU.S. patent application Ser. No. 12/522,252, which is herebyincorporated herein in its entirety by reference. A global positioningsystem (“GPS”) device 52 is preferably mounted to the tractor and inelectrical communication with the planter monitor 50 for transmittingthe current global location of the tractor 5 to the planter monitor 50.

In operation, the planter monitor 50 may be provided with a prescriptionmap file indicating the population rate to be planted at each globallocation in a field. As the planter traverses the field, the plantermonitor 50 commands the row units 16 to plant at the population ratecorresponding to the global location currently indicated by the GPSdevice 52. Simultaneously, the seed sensors 420 report the deposition ofeach seed to the planter monitor 50 and the planter monitor preferablyrecords the location of each seed and calculates the actual prescriptionrate for each location in the field.

FIG. 2 illustrates a top view of a combine 70, such as that illustratedin U.S. Pat. No. 6,226,969, including a head 77 for harvesting crops.The combine 70 preferably includes a yield sensor 440 (FIG. 3) formeasuring the near-instantaneous amount of crop being harvested. Theyield sensor 440 preferably comprises a sensor configured to measure theflow or amount of grain being harvested, such as an impact-type sensoras disclosed in U.S. Pat. No. 5,561,250, or other types of yield sensorssuch as disclosed in Applicant's co-pending U.S. Provisional PatentApplication No. 61/644,367, both disclosures of which are herebyincorporated herein in their entireties by reference. The yield sensor440 is in electrical communication with a cab-mounted yield monitor 72,which preferably incorporates a graphical user interface, such as thatdisclosed in Applicant's co-pending U.S. Provisional Patent ApplicationNo. 61/644,367, previously incorporated by reference. The yield monitor72 is preferably configured to calculate a yield measurement using asignal from the yield sensor 440 and to display and record the resultingyield measurement. A GPS device 75 mounted to the combine 70 is inelectrical communication with the yield monitor 72.

In operation, the yield sensor 440 measures the flow rate or amount ofclean grain separated from the crop after being drawn in through head77. The yield sensor 440 then transmits the resulting yield measurementto the yield monitor 72. Simultaneously, the GPS device 75 transmits acurrent global location of the combine to the yield monitor 72. Theyield monitor 72 preferably displays and records the yield measurementand the associated global location. As a result, a spatial map of yieldmeasurements in the field being harvested may be displayed to the userin the field and is preferably stored for later use.

A system 400 for gathering, comparing and analyzing planting and yielddata obtained as described above is illustrated in FIG. 3. The combineGPS device 75 is in electrical communication with the yield monitor 72.The yield monitor 72 is preferably in electrical communication with theyield sensor 440. The planter GPS device 52 is in electricalcommunication with the planter monitor 50. The planter monitor 50 ispreferably in electrical communication with one or more clutches 425,drives 427, and seed sensors 420. Both monitors 50,72 communicate datato a computer 450 via one or more data transfer devices 410. Thecomputer 450 is preferably configured to match planting data to yielddata for each location in the field and to perform analysis of the samedata as described further herein. In some embodiments, the yield monitor72 and the planter monitor 50 may be the same unit containing thesoftware for serving both as a planter monitor and as a yield monitorand having the features and functionalities as described above. In otherembodiments, the functions performed by the computer 450 are performedby the monitors 72,50, eliminating the necessity of any data transferdevice 410.

In some embodiments, the computer 450 is additionally in datacommunication (as, for example, by an Internet connection) with a server430. In such embodiments, the computer 450 and other computers 450-1operated by other users may transmit planting and harvesting data to theserver 430. The same data are preferably retrieved by the computer 450for use in comparing results among fields.

Plot Creation and Harvesting

Referring to FIG. 4, a planter 10 as described above is illustrated inplanting operations in a field 100, resulting in a planted area 190. Theplanter 10 plants the field 100 at a primary population rate indicatedby reference numeral 110. The primary population rate 110 constitutes abase rate which the user has determined is desirable for the field 100.As an example, a primary population rate for planting corn may be 30,000seeds per acre. The user is preferably enabled to experiment with theyield results of a different population by planting at a secondarypopulation rate indicated by reference numeral 120 in a plot 160 withinthe same field. As an example, a secondary population rate for plantingcorn may be 32,000 seeds per acre.

In order to generate the plot 160 in which the secondary population rate120 is planted as illustrated in FIG. 4, the planter monitor 50 (FIG. 1)preferably changes the commanded population rate to the secondarypopulation rate 120 when the GPS device 52 reports that it has reached afirst boundary 162. The monitor 50 then changes the commanded populationrate back to the primary population rate 110 when the GPS device 52reports that it has reached a second boundary 164.

As illustrated in FIG. 5, a combine 70 as described above is illustratedharvesting the field 100 which has been provided with the plot 160. Theplanted but unharvested area is indicated by reference numeral 195. Itshould be appreciated that a single yield sensor 440 typically measuresthe rate or amount of grain being harvested across the entire header 77(FIG. 2). Thus when the combine crosses the boundary 164 and beginsharvesting from the plot 160, the header 77 is preferably aligned toharvest only from the plot 160. In this manner, when reviewing collectedyield data it is possible to distinguish between yield results for theprimary population rate 110 and the secondary population rate 120.

The results of several methods of placing multiple plots in a singlefield 100 are illustrated in FIGS. 6-8. In FIG. 6, the method used toplant the plot 160 is repeated at a different location in the field inorder to generate a second plot 170 in which a tertiary population rateindicated by reference numeral 122 is implemented. In FIG. 7, theplanter 10 generates two side-by-side plots 160 and 170 in whichpopulation rates 120 and 122 are implemented respectively. Theside-by-side plots of FIG. 7 are generated by varying the populationrate commanded to individual row units 16 or groups thereof across thetoolbar 14. In order to accomplish this method, a separately controlleddrive is provided to the row units 16 or groups thereof as described inU.S. Pat. No. 6,070,539, which is hereby incorporated by referenceherein in its entirety. When generating such side-by-side plots, theplanter 10 is preferably enabled to plant a buffer area 165 planted atthe primary population rate 110 in between the plots 160,170. In FIG. 8,a master plot 150 including multiple end-to-end plots 160, 170, 169,165, and 166 in which population rates 120, 122, 124, 110, and 126 areplanted respectively. This method accomplished by changing the commandedpopulation rate between each plot. As illustrated in FIG. 8, the plantermonitor 50 changes the commanded rate directly between non-primarypopulation rates (as between, e.g., plots 169 and 170). In addition, theplanter monitor 50 commands the primary rate 110 in a buffer area 165between non-primary population rates (as between, e.g., plots 169 and166).

As illustrated in FIG. 9, the planter 10 is enabled to plant a singleplot using multiple passes. A plot 160 having secondary population rate120 may be planted in two plot sections 160-1, 160-2. The populationrate commanded to a group of left-hand row units 16 is changed whencrossing an upper boundary of the plot 160 in order to plant the firstplot section 160-1. Likewise, the population rate commanded to the sameor a different group of left-hand row units 16 is preferably changedwhen crossing a lower boundary of the plot 160 in order to plant thesecond plot section 160-2.

Plot Size and Location

Multiple factors affect the preferred size and placement of each plot160. Referring to FIG. 10, each plot 160 preferably has a critical areaA in order to obtain results upon harvesting having a desiredstatistical significance. As illustrated, the plot 160 has a length Lalong the direction of planting and harvesting travel and a transversewidth W. The width W is preferably a multiple of the width of combinehead 77 such that the combine 70 may harvest the entire plot 160 withoutsimultaneously drawing in crops planted at the primary population rate.Further, the desired minimum length L depends in part on the resolutionof the combine yield sensor. That is, different styles or models ofyield sensors have varying ability to determine whether the flow ratesor amounts of grain measured near the fore and aft boundaries of theplot are associated with the plot area or an adjacent area. Where thiseffect is more significant, longer plot lengths L are preferred.

The desired location of the plot is preferably determined in part by thesoil types or the soil productivity across the field. The field 100 ofFIG. 10 includes regions having soil types indicated by referencenumerals 414,410, and 412. As illustrated, the plot 160 is preferablyplaced on the predominant soil type 410 of the field 100 (i.e., thatpresent in the largest area of the field). The plot 160 is preferablyplaced such that the plot is a minimum distance D2 from any soil typeother than the soil type of the plot. It should be appreciated that thepreferred minimum distance D2 depends on the resolution of the yieldsensor. Likewise, the plot 160 is preferably placed such that the plotis a minimum distance DI from any field boundary or waterway.

Referring to FIG. 11, the plot shape may be varied in order to generatea plot having the desired size and location. The field of FIG. 11includes soil types 410,412, and 414, among which soil type 410 ispredominant as illustrated. In order to plant two plots having a desiredcritical area A within the predominant soil type 410, a first plot 170having a length L1 and width WI is planted along with a second plot 160having a length 12 and width W2.

Automatic Plot Placement and Analysis Methods

A process 300 of placing plots in a field during planting is illustratedin FIG. 13. At step 302, the planter monitor 50 preferably prompts theuser to enter GPS offsets for the planter, i.e., the travel-directionand transverse offsets between the GPS device 52 and each row unit ofthe planter. At step 305, the monitor 50 preferably prompts the user toprovide a set of plot selection parameters and a set of implementcharacteristics. In order to accomplish this step, the planter monitorpreferably displays a screen 1400 for receiving user input asillustrated in FIG. 16 on the graphical user interface 55. In order toenter implement characteristics, the screen 1400 preferably includes aninterface 1410 for entering the width (or number and spacing of rows) ofthe combine head to be used in harvesting and the width (or number andspacing of rows) of independently controlled sections of the planter tobe used in planting, an interface 1450 for selecting the type of crop tobe planted, and an interface 1440 for selecting the type and model ofyield sensor to be used in harvesting. In order to enter plot selectionparameters, the screen 1400 preferably includes an interface 1420 forentering the amount of variation in population desired and an interface1430 for entering the percentage of the field acreage that should be putinto plots. In other embodiments, the interface 1430 allows the user toselect the ratio between total acreage of plots within a base rate zone(FIG. 18) and the acreage of the base rate zone.

The interface 1420 preferably allows the user to set a maximumprescription variation 1424 and a minimum prescription variation 1422.In some embodiments, the interface 1420 additionally allows the user toselect a preferred statistical variation (e.g., a standard deviation) ofthe plot prescription values. It should be appreciated that some of theplot selection parameters comprise user risk preferences since theamount of acreage placed in plots and the variation in population of theplots represents a quantum of economic risk taken by the user in orderto learn optimal population in future seasons. It should be appreciatedthat the user interfaces may comprise text entry boxes, drop-down menusor sliding scales as illustrated in FIG. 16, or any other suitableinterfaces as are known in the art.

Returning to FIG. 13, at step 310 the planter monitor 50 preferablydetermines a set of plot characteristics including the location of theplots, the size of the plots, and the population rates to be plantedwithin the plots. A preferred process for carrying out step 310 of FIG.13 is illustrated in detail in FIG. 14. In carrying out the steps of theprocess in FIG. 14, the planter monitor 50 preferably displays a plotplacement screen 1800 as illustrated in FIG. 18. At step 1902, theplanter monitor 50 preferably identifies a field boundary 1805. In someembodiments, the field boundary 1805 is accessed from a file containingglobal positioning vertices recorded by the user by driving the boundaryof the field with a GPS device as is known in the art. In otherembodiments, the field boundary 1805 is accessed in a file containingglobal positioning vertices entered by the user, e.g., by drawing aboundary around an aerial image of the field as is known in the art. Atstep 1905, the planter monitor 50 preferably identifies base rate zones1810 within the field boundary 1805. In FIG. 18, two base rate zones1810-1,1810-2 have been identified, separated by a base rate boundary1820. Base rate zones 1810 are preferably those regions in which thesame base population rate is desired. In some embodiments, the base ratezones 1810 are identified by accessing a USDA soil type map includingsoil type polygons (e.g., as disclosed in Applicant's co-pending PCTApplication No. PCT/US11/68219, which is hereby incorporated herein inits entirety by reference, and determining the geometric unions betweenthe field boundary and one or more soil type polygons. In otherembodiments, the base rate zones 1810 comprise any region in whichcertain spatial characteristics of the field (e.g., soil type, drainagefeatures, and elevation) are common. At step 1910, the planter monitor50 preferably allows the user to set the population rates in the baserate zones 1810.

Continuing to refer to FIG. 14, at step 1915, the planter monitor 50preferably identifies a valid plot placement region 1830 within eachbase rate zone 1810. As illustrated in FIG. 18, the valid plot placementregions 1830-1,1830-2 are identified as the regions separated from thefield boundary 1830 and the base rate boundary 1820 by a certain minimumdistance or minimum distances, which minimum distances are preferablydetermined as discussed herein with respect to FIG. 10.

Continuing to refer to FIG. 14, at step 1915, the planter monitor 50preferably determines the plot dimensions based on the implementcharacteristics entered by the user at step 305 of process 300. Thisdetermination is preferably made as discussed herein with respect toFIG. 10. At step 1925, the planter monitor 50 preferably places plots1850 (FIG. 18) within the valid plot placement regions 1830. The plotplacement preferably satisfies the plot selection parameters entered bythe user at step 305 of process 300. For example, the ratio between atotal area of plots 1850 and a total area of the field boundary 1805 ispreferably equal to the ratio selected by the user using interface 1430of screen 1400 (FIG. 16). The plot placement preferably satisfies a setof plot placement rules preferably preloaded in the memory of theplanter monitor 50. For example, the plot placement rules preferablyrequire a minimum number of adjacent base rate cells 1852 having aminimum area. In some embodiments, the minimum number is three and theminimum area is the same as the area of plots 1850, resulting in the“checkerboard” pattern illustrated in FIG. 18. In other embodiments, theplot placement rules may require maximum possible distance between plots1850 while still satisfying the desired total plot acreage.

Continuing to refer to FIG. 14, at step 1930, the planter monitor 50preferably selects the plot rates to satisfy the distributionpreferences entered by the user in step 305 of process 300. At step1935, the planter monitor 50 preferably displays the proposed plotplacement to the user and requests user approval of the plot placement,e.g., by displaying an interface 1890 (FIG. 18). At step 1940, if theproposed plot placement has been rejected, then at step 1945 the plantermonitor 50 preferably allows the user to reject individual undesiredplots, and then repeats steps 1925 through 1935 without placing a plotnear the rejected location. Once the proposed plot placement isaccepted, the planter monitor 50 saves a prescription map including theproposed plot placement at step 1950.

In some embodiments of the process illustrated in FIG. 14, the plantermonitor 50 randomly selects among potential plot areas, displays therandom selection to the user, and allows the user to reject individualplot areas or reject the entire map and request a different randomizedset of plots.

Returning to FIG. 13, once the planned plot locations have been set theplanter 10 preferably begins planting at the primary population rate(e.g., rate 110 in FIG. 4) at step 317. At step 320, upon encountering aplot boundary (e.g., boundary 162 in FIG. 4), the planter monitor 50commands the rows crossing the boundary to plant at the plot populationrate (e.g., rate 120 in FIG. 4). At step 322, the planter monitor 50preferably displays a notification to the user that the plot populationrate has been activated. The notification may comprise a map indicatingthe plot locations and the current location of the planter, or an alarmwindow. It should be appreciated that such a notification is preferredbecause most planter monitors continuously display the currently activepopulation rate to the user, and an unexplained change in populationduring planting could confuse the user. The planter monitor 50 may alsopermit the user to override the plot during planting, e.g., byinstructing the planter monitor 50 to command the primary populationrate in spite of the previously planned plot.

At step 330, upon leaving the plot area (e.g., by crossing boundary 164in FIG. 4), the planter monitor 50 again commands the primary populationrate. At step 335, the planter monitor 50 preferably displays anotification to the user that the plot area has been exited. If theplanter monitor 50 determines at block 337 that the entire plot has notbeen completed, then steps 320-335 are repeated each time the planterpasses through another section of the plot (e.g., section 160-2 in FIG.9). Once the planter monitor 50 determines that the entire plot has beencompleted, at step 340 the planter monitor 50 preferably verifies andstores the location of the completed plot.

Continuing to refer to FIG. 13, at step 341, the yield monitor 72preferably prompts the user to enter the GPS offsets associated with thecombine, i.e., the travel-direction and transverse offsets between theGPS device 75 and the row units of the combine. During harvesting atstep 342, the yield monitor 72 preferably alerts the user tomisalignment of the combine head 77 with each plot such that the headdoes not harvest crop outside the plot area together with crops plantedat the base rate or other rates. This step may be accomplished using ahead correction screen 1700 as illustrated in FIG. 17. The headcorrection screen 1700 preferably includes a map 1710 illustrating thealignment of the head 77 with the plot 160 and a visual indicator 1720indicating the direction of any required correction and preferably theamount of correction expressed in an integer number of rows.

Returning to FIG. 13, at step 345 the yield monitor 72 records theharvested yield for each location in the field. At step 350, thecomputer 450 (see system 400 of FIG. 3) analyzes the yield results bycomparing the yield within the plot area with yields in other areas inthe same field or other fields. The computer 450 overlays and comparespopulation rates to yields for corresponding locations in the field. Forexample, as illustrated in FIG. 12, the computer 450 compares thepopulation rate A in planting map layer 502 to the corresponding yield Bin yield map layer 504.

A preferred process for carrying out step 350 of FIG. 13 is illustratedin FIG. 15. At step 351, the computer 450 preferably ranks theprescription by yield at each location in the field. For example, if amaster plot 150 was planted as illustrated in FIG. 8, the computer 450would rank each population rate according to the resulting yield. Asimilar analysis is preferably performed where a set of side-by-sideplots has been placed as illustrated in FIG. 7. At step 353, thecomputer 450 preferably determines an average yield for all locations inthe field at each population rate. Thus an average yield is determinedfor each set of plots at which a given plot population rate was planted,as well as for the primary population rate. At step 354, the computer450 preferably ranks the population rates according to their averageyield across the entire field. At step 355, the computer 450 preferablyobtains population rates and yield results for the same soil type fromdifferent fields uploaded from different computers 450-1 (see discussionwith respect to system 400 of FIG. 3) and determines an average yieldfor each population rate across multiple fields. At step 356, thecomputer 450 preferably ranks the population rates by average yield forevery field for which data was obtained at step 355.

In some implementations, comparisons between yields obtained fromvarious population rates are performed across seasons. For example, theyield obtained from a given population rate for a particular field arepreferably averaged with yields for the same population rate and fieldfrom prior years before comparison with other population rates.

Returning to FIG. 13, at step 360 the computer 450 generates a newprescription recommendation based on the yield analysis performed atstep 350. For example, a new primary population rate may be recommendedbased on the first-ranked population rate for the entire field.Additionally, location-varying population rate may be recommended wheredifferent population rates were first-ranked in different areas of thefield.

Although the systems and methods disclosed herein are illustrated anddescribed with respect to the rate at which seeds are planted, in otherembodiments the same systems and methods are be applied to other cropinputs applied using variable application implements other thanplanters. For example, in some embodiments the rate at which liquidfertilizer is applied using a variable rate application system is variedand the resulting yields are obtained after harvesting using the methodspresented herein. In other embodiments, a system for planting differentseed varieties during planting (e.g., those systems disclosed in U.S.Pat. Nos. 5,915,313 and 7,418,908, which are hereby incorporated hereinin their entirety by reference) could be used to plant plots ofdifferent varieties using the methods presented herein.

The foregoing description is presented to enable one of ordinary skillin the art to make and use the invention and is provided in the contextof a patent application and its requirements. Various modifications tothe preferred embodiment of the apparatus, and the general principlesand features of the system and methods described herein will be readilyapparent to those of skill in the art. Thus, the present invention isnot to be limited to the embodiments of the apparatus, system andmethods described above and illustrated in the drawing figures, but isto be accorded the widest scope consistent with the spirit and scope ofthe appended claims.

1.-20. (canceled)
 21. A method for generating a plot in a field, theplot to be planted with a planter having row units, the method,comprising: receiving a set of plot selection parameters specifying plotcharacteristics of a plot in a field and a crop to be planted in theplot; analyzing a first crop yield of a first region with a second cropyield of a second region, wherein the field is divided into at least thefirst region and the second region, the first region assigned a firstpopulation rate of the crop planted in the first region and the secondregion assigned a second population rate of the crop planted in thesecond region; ranking the first population rate and the secondpopulation rate according to the first crop yield and the second cropyield; and generating, based on the set of plot selection parameters anda result of the ranking, a prescription map including the plot in thefield and a plot population rate of the crop to be planted in the plot.22. The method of claim 21, further including: controlling anapplication rate based on the prescription map.
 23. The method of claim22, further including: displaying a location of the plot duringharvesting.
 24. The method of claim 21, further including based on a setof implement characteristics, determining plot dimensions of the plot.25. The method of claim 24, wherein the set of implement characteristicsincludes implement characteristics of equipment to be used in harvestingthe field.
 26. The method of claim 24, wherein the set of implementcharacteristics includes a width or number of rows of a combine head tobe used in harvesting the field.
 27. The method of claim 21, wherein theprescription map including the plot includes a location of the plot. 28.The method of claim 27, wherein the set of plot selection parametersincludes a risk preference.
 29. The method of claim 27, wherein the setof plot selection parameters includes a fraction of acreage to be placedin plots.
 30. The method of claim 21, wherein the prescription mapincluding the plot includes a prescribed application rate within theplot.
 31. The method of claim 30, wherein the set of plot selectionparameters includes a desired variation in application rate.
 32. Amethod of generating a seed population prescription map includingmultiple base rate zones, and multiple plots within each base rate zone,the method comprising: determining plot dimensions based on an implementcharacteristic of an agricultural implement used to harvest a crop froma plot in a field or plant the crop in the plot in the field;determining at least one plot location of at least one plot within thefield, wherein determining the at least one plot location is based on aplacement rule that requires a minimum number of base rate cellsadjacent to the at least one plot, the base rate cells having a minimumarea; and generating, based on the plot dimensions and the at least oneplot location, a prescription map including the at least one plot placedin the field.
 33. The method of claim 32, further including: identifyinga field boundary; identifying multiple base rate zones within the fieldboundary; assigning a base population rate to each base rate zone;identifying valid plot placement regions within each base rate zonebased on a first placement rule; determining plot dimensions based on afirst input; wherein the first input comprises a width or number of rowsof a combine head to be used in harvesting a field planted according tothe prescription map.
 34. The method of claim 32, further including:receiving second input that comprises a desired ratio between an area ofa group of plots and an area of a region enclosing the group of plots.35. The method of claim 32, further including: determining populationrates within each plot based on a third input.
 36. The method of claim35, wherein the third input includes a desired variation in populationrates.
 37. The method of claim 32, further including: providing agraphical user interface to accept or reject plot locations; andaltering at least one plot location based on a rejection input receivedvia the graphical user interface.